Classification Of Odontogenic Tumors Research Articles

Central odontogenic fibroma granular cell variant: A case report and review of the literature

In 1992 the World Health Organization (WHO), in its revised classification of odontogenic tumors, 1 Kramer IRH Pindborg JJ Shear M Histological typing of odontogenic tumors. in: World Health Organization International Histological Classification of Tumours (ed 2). Springer-Verlag, Berlin, Germany1992: 22 Google Scholar defined the odontogenic fibroma (OF) as a benign ectomesenchymal proliferation characterized by fibroblastic tissue containing varying amounts of apparently inactive odontogenic epithelium. The WHO distinguishes between a central (intraosseous) and peripheral forms but does not subdivide the central form of OF. Other authors 2 Gardner DG The central odontogenic fibroma: An attempt at clarification. Oral Surg Oral Med Oral Pathol. 1980; 50: 425 Abstract Full Text PDF PubMed Scopus (89) Google Scholar , 3 Gardner DG Central odontogenic fibroma current concepts. J Oral Pathol Med. 1996; 25: 556 Crossref PubMed Scopus (64) Google Scholar have distinguished between a so-called simple type and a complex type commonly referred to as the WHO type. The WHO type is more cellular than the simple type, with odontogenic epithelial cells forming a substantial part. Calcifications and abundant collagen fibers are often exhibited. 2 Gardner DG The central odontogenic fibroma: An attempt at clarification. Oral Surg Oral Med Oral Pathol. 1980; 50: 425 Abstract Full Text PDF PubMed Scopus (89) Google Scholar , 3 Gardner DG Central odontogenic fibroma current concepts. J Oral Pathol Med. 1996; 25: 556 Crossref PubMed Scopus (64) Google Scholar

Genetic portrait of malignant granular cell odontogenic tumour

Odontogenic tumours are rare neoplasms whose classification is sometime controversial. Among these entities, granular cell odontogenic tumour (GCOT) is extremely rare and usually has a benign clinical behaviour. While the histogenesis of GCOT remains to be clarified, we documented the existence of a malignant counterpart of this neoplasm and proposed the name of malignant GCOT. Expression profiling by cDNA microarrays is a molecular technology that enables a global gene expression analysis. By using cDNA microarrays, we identified in malignant GCOT several genes with significantly differentially regulated genes when compared to non neoplastic tissues. These cancer specific genes include a range of functional activities: (1) transcription, (2) signaling transduction, (3) cell-cycle regulation, (4) apoptosis, (5) differentiation and (6) angiogenesis. In conclusion, we show that cDNA microarrays is a useful approach to investigate the biology of tumours. Moreover, this technology might lead to identification of gene targets for cancer therapy and to molecular classification of odontogenic tumours.

Revision of the 1992-edition of the WHO histological typing of odontogenic tumours. A suggestion.

Classification of odontogenic tumours is an academic exercise that has developed over the last 150 years. It was not until 1971 when a 5-year collaborated effort, organized by the World Health Organization (WHO), resulted in the first consensus on taxonomy of odontogenic tumours. The appearance of this first authoritative guide to the classification of odontogenic tumours marked the start of an era of quite intensive interest for studying this particular field of oral pathology. An updated 2nd edition of the WHO classification was published in 1992.

Ameloblastic fibroma and related lesions: current pathologic concept.

Ameloblastic fibroma (AF) is a true mixed tumor, in which the epithelial and the ectomesenchymal elements are neoplastic. There are two rare variants of AF; granular cell AF and peripheral AF. Ameloblastic fibrosarcoma is a rare tumor, and is regarded as the malignant counterpart of the benign AF. Recent immunohistochemical study using MIB-1 shows labelling indices in the mesenchymal component of the recurrent AF and ameloblastic fibrosarcoma are quite high, in contrast with the conventional AF. Ameloblastic fibrodentinoma is a histologic variant of AF in which dentin or dentinoid tissue has formed, but there is no eveidence that ameloblastic fibrodentinoma exhibit a different biologic behavior than ordinary AF. Ameloblastic fibro-odontoma is a lesion similar to AF, but also showing inductive changes that lead to the formation of both dentin and enamel. Some lesions diagnosed as ameloblastic fibro-odontoma are probably developing odontoma, but the others should not be considered as hamartomatous in nature, since there are rare cases of ameloblastic fibro-odontoma showing true neoplastic behavior, and since the existence of malignant variant is evident. In revised WHO's classification of odontogenic tumors, the terms "ameloblastic fibrodentinoma" and "dentinoma" are used synonymously, however, there are histologic difference between several cases reported previously as "dentinoma" and ameloblastic fibrodentinoma.

Odontogenic tumors: A demographic study of 759 cases in a Chinese population

Seven hundred fifty-nine cases of odontogenic tumors retrieved from the files of College of Stomatology, West China University of Medical Sciences were classified according to the World Health Organization's Histological Classification of Odontogenic Tumors and compared with similar reports from other countries. Among these cases, 93.9% of the tumors were benign and 6.1% were malignant. Ameloblastomas predominated (58.6%) with a predilection for the mandible, while odontomas, generally regarded as the most frequent odontogenic tumor in North America, only accounted for 6.7%, the fourth most common tumor in this series. The mandible and the maxilla were divided into eight anatomic regions, and the distribution of each odontogenic tumor type amongst these regions was recorded. The relative incidence of each tumor type, patient age and gender were also compared with data from other selected large series. Geographic differences were noted in the relative incidence of ameloblastoma, odontoma and malignant odontogenic tumors among the Chinese/African, North American and Turkish/German groups. Ameloblastoma and malignant odontogenic tumors are not considered rare in a Chinese population.

Odontogenic classification of craniopharyngiomas: a clinicopathological study of 54 cases.

Based on the striking histological similarity of craniopharyngiomas and some odontogenic tumours, we reclassified a series of 54 craniopharyngiomas (52 adamantinomatous and two papillary variants) according to the WHO classification of odontogenic tumours. Twenty-seven tumours (50%) corresponded histologically to calcifying odontogenic cyst. 13 tumours (24%) to ameloblastoma, and eight (15%) tumours showed features of both calcifying odontogenic cyst and ameloblastoma either within the same specimen or in specimens derived from different resections. Rare tumours included three cases resembling calcifying epithelial odontogenic tumour and one case resembling adenomatoid odontogenic tumour. No odontogenic counterpart could be established for papillary craniopharyngiomas. The two major subtypes, i.e. craniopharyngioma corresponding to calcifying odontogenic cyst and craniopharyngioma corresponding to ameloblastoma, did not differ in their basic clinical features. Our data confirm and extend the close histological resemblance between adamantinomatous craniopharyngioma and odontogenic tumours and cysts. Furthermore, although calcifying odontogenic cyst and ameloblastoma arising in the jaw differ in clinical presentation and outcome, our study did not reveal clinical differences for the corresponding subtypes of craniopharyngioma.

Histological Classification of Odontogenic Tumors and Cysts

Histological Classification of Odontogenic Tumors and Cysts

リンパ節転移を伴った再発下顎エナメル上皮腫の１例

Conventionally, an ameloblastoma with metastasis was diagnosed as a malignant ameloblastoma. In the new classification of odontogenic tumors revised by the WHO in 1992, the diagnosis of malignant ameloblastoma is based on cytological criteria. Malignant ameloblastoma is defined as a neoplasm in which the pattern of an ameloblastoma and the cytological features of malignancy are shown by the primary lesion in the jaws and/or any metastatic lesion.We reported a case of recurrent ameloblastoma of the right mandibule with metastatic lymph nodes six years after primary treatment. There was metastasis to the buccal and submandibular lymph nodes on the right side. There were no cytological features of malignancy in either the mandibular lesion or metastatic lymph nodes.According to general concepts of pathology, the criteria for malignancy includes recurrence and metastasis as well as cytological features. The criteria for malignant ameloblastoma require further discussion.

Odontogenic tumors: analysis of 289 Nigerian cases.

Two hundred and eighty-nine cases of odontogenic tumors that accumulated in the files of the biopsy service of the Lagos University Teaching Hospital during a period of 21 years were analysed and categorised according to the most recent WHO classification of odontogenic tumors. Odontogenic tumors constituted 19% of all oral/jaw tumors and tumor-like lesions. Ameloblastoma, which accounted for 58.5% of odontogenic tumors in the series, was the most common, and showed a predilection for males and the posterior mandible. 94.8% of odontogenic tumors were benign, while malignant odontogenic tumors accounted for 5.2%. Odontogenic carcinoma was the most prevalent malignant odontogenic tumor; it showed a prediction for the mandible and occurred at a mean age of 37 years.

Ｄｅｓｍｏｐｌａｓｔｉｃ ａｍｅｌｏｂｌａｓｔｏｍａに関する臨床的，Ｘ線学的ならびに病理学的検討

Some ameloblastomas consist of sparse small nests and strands of odontogenic epithelium associated with desmoplastic stroma. This type of ameloblastoma was designated as desmoplastic ameloblastoma in the new WHO classification of odontogenic tumors in 1992. Over the past 22 years from 1970 to 1991, we diagnosed 4 cases of desmoplastic ameloblastoma among 124 primary cases of ameloblastoma, and analyzed them clinically, radiologically and histopathologically.1. The age at the initial visit was the third decade or over. Three cases occurred in the mandible and one case in the maxilla. The incidence of desmoplastic ameloblastoma was 3.2% of all ameloblastomas in the jaw bones.2. Three cases occurred in the anterior to the first premolar region and one case in the anterior to the first molar. These tumors seemed to develop from the alveolar process.3. Radiologically, all cases showed a honeycomb appearance containing mottled or dotted radiopacities with ill-defined margins.4. Divergency of tooth roots was seen in all cases, and some roots showed prominent resorption.5. Grossly, all tumors were solid type. Histologically, small sparse nests which showed acanthomatous type, stroma containing abundant collagen fibers, and many irregularly shaped areas of lamenar bone were observed. In the irregular bone, bone resorption and formation was seen concomitantly. The tumor invaded the adjacent bone marrow.6. Marginal resection was performed in 3 cases and enucleation followed by curettage in one case. No recurrence was noted.

The WHO Histological Typing of Odontogenic Tumours. A commentary on the Second Edition.

This article introduces the revised World Health Organization (WHO) classification of odontogenic tumors and jaw cysts and certain bone lesions that either are peculiar to the jaws or have distinctive features in that location. The new and revised classification is compared with the previous version, the reasons for the changes are outlined, and reference is made to a number of newly characterized lesions that have been included.

New classification of odontogenic tumours

New classification of odontogenic tumours

Epithelial jaw cysts: 10 years of the WHO classification.

Numerous papers on epithelial jaw cysts have appeared in the decade since the publication in 1971 of the WHO histological classification of odontogenic tumours, jaw cysts, and allied lesions. Despite clarification of certain cyst varieties no major revisions are necessary. The following minor modifications are proposed. In the developmental odontogenic group, the terms keratocyst and follicular are preferred to primordial and dentigerous. The alveolar cyst of infants is categorised separately from the gingival cyst of adults. The developmental lateral periodontal cyst is included as a distinctive new type. In the non-odontogenic group the globulomaxillary is deleted as a unique entity, whereas the midpalatal cyst of infants is a new inclusion. To the inflammatory category are added the inflammatory follicular and inflammatory lateral periodontal varieties.

Considerations on the classification of odontogenic tumours

The histogenetic, organogenetic and embryological aspects of tooth development are used in 4 hypotheses which form a basis for understanding the formal genesis of benign odontogenic tumours. The ectomesenchyme which gives rise to odontoblasts and cementoblasts is distinguished from mesenchymal tissue. Using 4 histogenetic cell groups (epithelial, ectomesenchymal, neuroectodermal and mesenchymal), the various types of odontogenic tumour are discussed. A short analysis is presented of different odontogenic tumour classifications, and some principle problems of terminology and taxonomy are examined.

Calcifying epithelial odontogenic tumor: report of four cases

Calcifying epithelial odontogenic tumor associated with the mandible occurs rarely and is thought to be a distinct entity in the classification of odontogenic tumors since there is only slight histomorphologic similarity to the ameloblastoma. Calcifying epithelial odontogenic tumor associated with the mandible occurs rarely and is thought to be a distinct entity in the classification of odontogenic tumors since there is only slight histomorphologic similarity to the ameloblastoma.

Classification on Odontogenic Tumors a Suggestion

A classification of odontogenic tumors based on the developmental interdependence of dental tissues is suggested. The tumors are divided into two main groups, viz., epithelial and mesodermal tumors. The epithelial tumors are subdivided into purely epithelial tumors and epithelial tumors with inductive changes in the connective tissue. A revision of the prevailing concept according to which ameloblastomas are synonymous with epithelial odontogenic tumors is suggested and a new subdivision is introduced. The group of epithelial tumors with induction in the connective tissue comprises tumors composed of soft tissue and tumors containing the dental hard tissues in varying amounts.